[P07.143] Two Annual Cycles of Alemtuzumab Yield Durable Treatment Response 24 Months after Last Dose

Sibyl Wray, Knoxville, TN, CAMMS223 Study Group, San Antonio, TX

OBJECTIVE: To assess the durability of alemtuzumab's effect on sustained accumulation of disability (SAD) and relapse rate in patients with relapsing remitting multiple sclerosis (RRMS). BACKGROUND: CAMMS223, a randomized, open-label, rater-blinded, phase 2 study, compared the safety and efficacy of alemtuzumab to interferon beta-1a (IFNB-1a) in treatment-naive patients with RRMS. Alemtuzumab was significantly more effective than IFNB-1a at reducing SAD and relapse rate through 36 months. Those analyses combined patients receiving 2 annual alemtuzumab cycles with those receiving 3 cycles. The optimal number of alemtuzumab cycles needed to maintain durable response is under investigation. DESIGN/METHODS: Patients with early, active RRMS (n=334) were randomized 1:1:1 to IFNB-1a (44mcg SC 3x/week); 24mg/day alemtuzumab; or 12mg/day alemtuzumab. Entry criteria included baseline EDSS 3.0, 2 MS episodes within 2 years, and 1 enhancing lesion on MRI. Alemtuzumab was IV-administered for 5 days at Month 0 and 3 days at Month 12, and in some patients, 3 days at Month 24. Efficacy endpoints included SAD (ie, a reduction in EDSS lasting 6 months) and relapse rate. Post hoc analyses compared patients receiving only [strike][/strike]2 cycles alemtuzumab (n=161) to all IFNB-1a-treated[strike][/strike][strike][/strike] patients (n=107). RESULTS: Two annual cycles of alemtuzumab, compared to 3x weekly IFNB-1a, reduced the risk of SAD by [strike][/strike]71% (p<.01[strike][/strike]) and relapse rate by [strike][/strike]83% (p<.0001[strike][/strike]) 12 months after the last dose of alemtuzumab. Signi[strike][/strike]ficant effects of alemtuzumab were still observed 24 months after the last dose with a 70% reduced risk of SAD (p<.001[strike][/strike]) and a 74% reduction in relapse rate (p<.0001). Notable alemtuzumab-related adverse events included infustion reactions, secondary autoimmunity, and predominantly mild to moderate infections. CONCLUSIONS/RELEVANCE: Twenty-four months after their last dose, alemtuzumab-treated patients continued to experience significant reductions in SAD and relapse rate compared to patients treated with 3x weekly injections of IFNB-1a. The mechanisms underlying alemtuzumab's durable effects are currently under investigation. Supported by: GENZYME
Category - MS and Related Diseases - Clinical Science

Thursday, April 30, 2009 7:00 AM

Poster Session VII: Multiple Sclerosis: Therapeutics II (7:00 AM-10:00 AM)